1. Field of the Invention
The present invention relates to a flat panel display device such as a liquid crystal display device and, more particularly, to a structure of supporting a flat display panel.
2. Description of the Prior Art
In recent years, as a device is becoming smaller, lighter, and thinner, a flat panel type electron display device (hereinbelow, called a flat panel display device) typified by a liquid crystal display device for use in various devices is also becoming thinner. The structure of supporting the flat display panel is also devised accordingly.
A conventional example of a liquid crystal display device having a backlight will be described herein below as an example of the flat panel display device.
As shown in FIG. 1, a conventional liquid crystal display device 1 comprises a rectangular liquid crystal panel 2 and a rectangular light guide plate 3 for backlight provided on the under face side of the liquid crystal panel 2. The liquid crystal panel 2 comprises substrate members 4 and 5 such as a pair of glass substrates, which are opposed to each other. Outer surfaces of the substrates 4 and 5 are provided with polarizers 6. The lower substrate 4 is provided with a matrix array of thin film transistors and thus which is called a TFT substrate to have a shutter function of controlling light from the light guide plate 3. The upper substrate 5 is provided with color filters (CF) of three primary colors for color display and thus which is called a CF substrate.
The liquid crystal panel 2 and the light guide plate 3 are laminated together with an inner holding frame 11 inserted therebetween. This laminated structure is housed in a container formed with a pair of outer holding frames 16 and 17. Each of the inner frame 11 and the outer frames 16 and 17 is made of a synthetic resin and formed in a rectangular frame shape.
On the inner holding frame 11, a holding wall 15 is formed in the circumferential direction. The liquid crystal panel 2 is disposed within the holding wall 15 such that end surfaces of the liquid crystal panel 2 are opposed to a holding face 15a of the holding wall 15.
A holding recess 12 is formed in the lower part of the inner holding frame 11. The light guide plate 3 is fit and held in the recess 12. The inner holding frame 11 is provided with a supporting portion or a spacer 13 so as to be interposed in the circumferential direction between the light guide plate 3 and the liquid crystal panel 2. The liquid crystal panel 2 is disposed over the light guide plate 3 via the spacer 13 in a state where the lower substrate 4 is in contact with the spacer 13.
As described above, the outer frames 16 and 17 as upper and lower holding fittings each of which is a frame member having an L shape in cross section are fit to the upper and lower parts of the inner holding frame 11 which holds the liquid crystal panel 2 and the light guide plate 3. By fitting the outer frames 16 and 17, the light guide plate 3 and the liquid crystal panel 2 are integrated with the inner holding frame 11. In such a manner, a liquid crystal display module is obtained.
Such a liquid crystal display module is attached to a casing for display of an information processor.
As shown in FIGS. 2A and 2B, the liquid crystal panel 2 is generally constructed so that two sides in the CF substrate 5 are arranged on the inner side from the end faces of the TFT substrate 4 to expose electrode terminals (not shown) provided along two sides which are orthogonal to each other in the TFT substrate 4. As shown in FIG. 2C, printed circuit boards 23 on which semiconductor ICs for control are mounted and the electrode terminals of the TFT substrate 4 are electrically connected via TCPs (Tape Carrier Packages) 24.
Such a liquid crystal display panel 2 is produced as follows. As shown in FIG. 3A, a panel 2a is prepared by adhering the substrates 4 and 5 having the same outer shapes. Along a predetermined shape (indicated by an alternately long and short dash line 41 in FIG. 3A), as shown in FIG. 3B, a cutting groove 201 is formed in the TFT substrate 4 by a deep penetrating cutter 21. After that, the panel 2a is turned upside down. A predetermined impact is applied to the panel 2a on the side opposite to the cutting groove 201 side by a hammer, thereby breaking only the TFT substrate 4.
Subsequently, as shown in FIG. 3C, a cutting groove is similarly formed in the CF substrate 5 by the deep penetrating cutter 21 along a predetermined shape (indicated by an alternate long and two short dashes line 51 in FIG. 3C). After that, the panel 2a is turned upside down and a predetermined impact is applied to the side opposite to the cutting groove side by a hammer, thereby breaking only the CF substrate 5.
In such a manner, as shown in FIG. 2A, the liquid crystal panel 2 made by the substrates 4 and 5 formed in the predetermined shapes is obtained.
As shown in FIG. 2B, the liquid crystal panel 2 obtained by cutting the outer sides is chamfered by polishing the corners on the surface and back face of the cut faces. In one of the sides in the longitudinal direction and one of the sides in the width direction having electrodes to which the TCPs 24 are connected, the corners on the surface side adhered to the CF substrate 5 of the TFT substrate 4 are also chamfered.
As shown in FIG. 2C, the printed circuit boards 23 are connected via the TCPs 24 to one of the sides in the longitudinal direction and one of the sides in the width direction having electrodes of the chamfered liquid crystal panel 2. After that, the resultant is fit in the holding walls 15 of the holding frame 11.
In the case of manufacturing the liquid crystal panel 2 by cutting the panel 2a in a predetermined outer shape as described above, the substrates 4 and 5 are cut almost in the same outer shape so that the cut faces are flush with each other in each of the other sides in the longitudinal and width directions to which the TCP 24 is not connected. As shown in FIG. 4, however, there is a case such that a deviation of about 0.3 mm at the maximum occurs between the TFT substrate 4 and the CF substrate 5 and a sharp edge 501 of the CF substrate 5 is exposed.
Since the deviation of the edge 501 is very small, chamfering cannot be performed. Consequently, the edge 501 has to be enclosed and held as it is in the holding walls 15 of the holding frame 11.
As shown in FIGS. 5A and 5B, when the liquid crystal panel 2 in which a deviation occurs between the TFT substrate 4 and the CF substrate 5 is supported together with the light guide plate 3 by the holding frame 11 to thereby form the liquid crystal display device 1, on or after attachment of the liquid crystal panel 2 to the holding frame 11, there is a case such that either the edge 401 of the TFT substrate 4 or the edge 501 of the CF substrate 5 which occurs due to the deviation between the substrates 4 and 5 cuts the holding face 15a of the holding wall 15.
When the holding face 15a of the holding wall 15 is cut, the following problem occurs. A dust cut from the holding wall 15 enters between the liquid crystal panel 2 and the light guide plate 3 and partially shields light from the light guide plate 3 and it disturbs display performed by the liquid crystal display device 1. The problem occurs similarly also in a reflection type liquid crystal display device employing a reflector in place of the light guide plate.
Since the holding frame 11 is provided in the thickness direction by the holding walls 15 so as to surround the liquid crystal panel 2, there are problems such that a detaching work of the liquid crystal panel 2 for test, maintenance or replacement is difficult and, moreover, it is very troublesome to attach the liquid crystal panel 2 to the holding frame 11.
Obviously, the problems occur not only in the liquid crystal display panel but also in the other flat panel display devices such as a plasma display device, each having two glass substrates which are disposed so as to face each other.
It is therefore an object of the invention to provide a flat panel type display device having a holding frame structure in which a holding frame is prevented from being cut by an edge of a flat type display panel such as liquid crystal display panel.
Another object of the invention is to provide a flat panel type display device having a holding frame structure capable of suppressing occurrence of a display failure caused by a dust.
Still another object of the invention is to provide a flat panel type display device having a holding frame structure in which a display panel can be easily attached and detached.
According to the invention, there is provided a flat panel display device comprising: a display panel obtained by disposing a pair of panels so as to face each other; a holding frame for supporting the back side panel in the display panel; and a surface side outer frame which faces the holding frame and supports the surface side panel in the display panel, wherein the holding frame has an end face supporting part and a peripheral supporting part which come into contact with an end face and a peripheral face, respectively, of the back side panel, and the distance between a supporting face upper end of the end face supporting part and a supporting face of the peripheral supporting part in the holding frame is smaller than the thickness of the back side panel.
In such a display device, the end face supporting part has a surface side projection which extends toward the outer frame, and a taper by which the distance between the supporting face upper end and the panel end face is gradually increased toward the outer frame is formed in the surface side projection. Consequently, when the liquid crystal panel is fit in the holding frame, the liquid crystal panel is smoothly guided along the tapers formed in the holding walls and is fit in the holding frame, so that the work of fitting the liquid crystal panel into the holding frame can be facilitated.
The end face supporting part maybe selectively provided. That is, since the end faces of the liquid crystal panel fit in the holding frame can be held by the notches formed in the holding walls, the work of detaching the liquid crystal panel at the time of test, maintenance or replacement of the liquid crystal panel can be facilitated.
In the flat panel display device, the display panel is a liquid crystal display panel and, on the side opposite to the side on which the liquid crystal display panel is supported in the holding frame, light guide plate housing walls for housing a light guide plate for backlight are provided and a back side outer frame for supporting the light guide plate is also provided.
In the flat panel display device, the display panel is a liquid crystal display panel, on the side opposite to the liquid crystal display panel in the holding frame, reflector housing walls for housing a reflector are provided and a back side outer frame for supporting the reflector is provided.
The invention is also characterized in that the area of the back side substrate is larger than that of the surface side substrate. Further, the ridgeline formed between the end face and a face which comes into contact with the periphery supporting part in the back side substrate is chamfered.
According to the invention, the end face supporting part is selectively provided at a corner of the holding frame so that the front end supporting part is apart from a corner of the back side substrate. For example, when notches are formed in the corners of the holding walls, the interference of the corners of the liquid crystal panel with the holding walls can be certainly prevented and the inconvenience caused by the interference of the corners of the liquid crystal panel with the holding walls can be prevented.
Furthermore, at least on one side of the display panel, end faces of the facing substrates are substantially flush with each other.
In the flat panel display device, the outer frame is comprised of a surface side outer frame and a back side outer frame, the surface side outer frame presses the other substrate in the display panel against the holding frame, and the back side outer frame presses the holding frame against the display panel.
According to the invention, there is provided a liquid crystal display device comprising: a light guide plate of a backlight as a plate-shaped light source; a liquid crystal panel having a pair of transmission panel members which are adhered to each other; and a holding frame for holding the peripheries of the light guide plate and the liquid crystal panel so that their faces are arranged in parallel, wherein holding walls which surround the liquid crystal panel are formed in the holding frame and each of the holding walls has a holding face which can come into contact with the end face of only one of the substrate members, on the side of one of the substrate members with respect to the boundary of the substrate members.
As described above, on the side of one of the substrate members with respect to the boundary of the panels, the holding face, which can come into contact with the end face of only one of the substrate members is formed in each of the holding walls surrounding the liquid crystal panel. Consequently, the inconvenience can be certainly prevented such that a dust generated when the edge at the boundary of the substrate members of the liquid crystal panel comes into contact with the holding wall on or after the attachment of the liquid crystal panel and thereby cuts the holding wall enters between the liquid crystal panel and the light guide plate and it causes a problem in display on the screen. Furthermore, since only the holding face can come into contact with only the lower substrate member with respect to the boundary of the panels, an inconvenience such that the edge formed by a deviation between the upper and lower substrate members interferes with the holding wall and cuts the holding wall can be certainly prevented.